With the growing and continued use of an increasingly broad variety of electronic devices in both commercial and industrial applications, the manufacturers of such devices are producing ever increasing numbers of articles. Furthermore, the variety of those electronic articles (integrated circuits, transistors, capacitors, etc.) continues to grow. Demands of users for higher quality and reliability have imposed increasingly greater requirements for more extensive and comprehensive inspection of these electronic components. Indeed, for some applications, one hundred percent inspection is a common requirement. Of course, any such inspection must be non-destructive with respect to the articles themselves.
One of the widely accepted methods for non-destructive testing of integrated circuits, transistors, capacitors, and other electronic components utilizes a scanning acoustic microscope. However, inspection by acoustic microscopy is frequently a relatively slow process, particularly as compared with other test procedures directed to inspection of the electronic functions of the devices. As a consequence, it is highly desirable to have an inspection mechanism with the capability of testing a substantial variety of electronic articles in an automated procedure. Even so, there are a number of problems that to be overcome in the utilization of acoustic microscopy for inspection procedures, particularly because inspection with an acoustic microscope usually requires that the article being inspected be immersed in water or some other liquid inspection medium during testing.
For many electronic components, particularly integrated circuits, the articles requiring inspection should be inspected while still in trays. Encapsulated integrated circuits and other like electronic articles can be loaded into trays, in orderly patterns, using trays that are especially designed to hold articles of a specific type. Typically, the test articles are arranged in a grid pattern of rows and columns. Often, the articles are packaged loosely in trays. The electronic leads of these electronic devices are often quite delicate, so that any handling may present a substantial problem. Often, the articles to be inspected are not secured in trays or other like supports, so that introduction of the articles into water or some other liquid test medium may cause some of the parts to float, usually due to surface tension of the liquid. Moreover, air bubbles may collect on top of and underneath the articles at the time of immersion.